The Hideout, the little-bar-that-could in the Chicago music scene, is celebrating its 21st anniversary this weekend with the return of its summer-ending block party. But this ostensibly feel-good story has some yellow flags attached.

The block party nearly went away for good when the club owners reassessed its purpose in recent years, and now that it has returned, the moment could be short-lived.

A Chicago real estate developer, Sterling Bay, recently reached a $105 million deal to buy 18 acres that includes much of the industrial property around the Hideout. Recent zoning changes for the property approved by the city have raised speculation that Sterling Bay is ticketing the area for major retail and residential projects.

What once used to be an out-of-the-way industrial zone with the Hideout as a blue-collar sanctuary may be transformed. Though the Hideout’s proprietors — husband and wife Tim and Katie Tuten and brothers Mike and Jim Hinchsliff — own their property, massive gentrification appears imminent. Anyone with a sense of Chicago music history immediately alights on the fate of the great Lincoln Avenue club Lounge Ax, which was eventually forced to shut its doors 17 years ago after its once-bohemian neighborhood was invaded by yuppies with fern bars in their eyes.

Should anything untoward happen to the Hideout it would be a major blow to a community of artists, fans and social activists that the club has long supported. Bloodshot Records uses the Hideout as something of a second home, but label co-owner Rob Miller speculated in a 2011 Tribune interview that the property around the club was likely too valuable to go undeveloped for much longer. “Someone sees this area,” he said, “and has a billion dollars in his eyes."

But Tim Tuten says the owners are resolute when they look ahead. And he’s pretty psyched about the block party, which is doubling down on indie artists who have persevered rather than trying to compete with the bigger Chicago summer festivals in vying for big-name headliners.

The artists include stellar rock bands such as local stalwarts Eleventh Dream Day and Jon Langford & Skull Orchard, Yo La Tengo spinoff Condo F----, and Antietam, the New Jersey-via-Louisville trio making a rare Chicago visit on the heels of one of its finest albums, “Intimations of Mortality.” On Sunday, the festival will celebrate the 20th anniversary of Steve Albini’s Electrical Audio studio with a lineup hand-picked by the recording engineer, including Man Or Astro-Man?, Screaming Females and Shannon Wright.

Click for more photos at The Hideout.

(Christine Connelly / for RedEye)

In an interview, Tuten reasserted his optimism — mixed with more than a hint of defiance — that the club, which was built in the 19th Century, would remain well into the 21st.

On the club’s future: “This was an intimate, handmade, Irish working-man’s bar. We come from a humble place, and our music is always relevant. The kind of events we do include fundraising for political organizations or social justice organizations. We do our part for the community, and we do it continuously. They can build towers around us, but we’ll be there as a reminder of where this city came from. We’ll be a reminder of the importance of authenticity. That should never get old.”

Why the block party took the last two years off: “The last one was in 2014, and we had 7,000 people each day, with Death Cab for Cutie and the War on Drugs. But we had a bad rainstorm the first night, and we almost had to call it off. It just came over me, I kept thinking we want the biggest festival we can to pack into our block. I was caught in a race to get bigger, and I realized it was a trap. Why is that festivals keep getting bigger — Riot Fest moves to Douglas Park, Pitchfork gets bought by Conde Nast, Lollapalooza expanded to four days? The Hideout needs to be small and well-curated. We got back to the idea of what’s more fun, what’s better — standing with 100,000 people in a big field or going to a backyard barbecue?”

On whether he likes being called the owner of a dive bar: “As with certain terms, you own it and liberate it. I grew up looking for regular bars, real bars, that’s what I was always look for. That’s what I found in the Hideout. There are dive bars and there are dumps. If you dive into something you’re into deep waters, a book, an experience. A ‘dive’ represents depth. And then you have hipsters who do things for style. If you go for style, you miss the point of the dive. Dives have regular people, a community. A lot of times a group will come into the Hideout for the first time because they heard about the dive on Wabansia surrounded by factories. And one or two will say, ‘This place sucks, I need a martini.’ It’s not for everybody.”